St. Paul's Cathedral in London, England, was originally built in 604 AD, but the cathedral that stood before the Great Fire of 1666 was primarily built in the 12th and 13th centuries. It was designed in the Gothic style and was one of the largest and most impressive churches in England at the time.

The cathedral was built from a combination of materials, including limestone, sandstone, and slate. The exterior was adorned with intricate carvings and statues, while the interior featured vaulted ceilings and stained glass windows.

The design of St. Paul's Cathedral was a collaboration between several architects and builders over the course of several centuries. The original Norman cathedral was rebuilt in the Gothic style in the 13th century, and further renovations and additions were made in the following centuries.

In 1666, a devastating fire swept through London, and St. Paul's Cathedral was one of the many buildings that were destroyed. The fire started in a bakery on Pudding Lane and quickly spread throughout the city, fueled by strong winds and dry weather conditions. Despite the efforts of firefighters and citizens, the fire burned for four days and destroyed more than 13,000 homes and other buildings.

The intense heat of the fire caused the cathedral's limestone pillars and walls to crack and crumble, and the wooden roof and furnishings were completely destroyed. The cathedral's famous spire, which had been added in the 16th century, also collapsed during the fire.

After the Great Fire, plans were made to rebuild St. Paul's Cathedral, and a competition was held to find a suitable design. The winning design was submitted by Christopher Wren, who oversaw the rebuilding of the cathedral in the late 17th and early 18th centuries. The new cathedral featured a baroque style and was larger and more grandiose than its predecessor, but it still maintained many of the original features and design elements of the previous cathedral.

After the Great Fire of 1666 destroyed the previous St. Paul's Cathedral, a commission was established by King Charles II to oversee the rebuilding of the cathedral. The commission was headed by Sir Christopher Wren, a prominent English architect who had previously designed several other notable buildings in London.

Wren's original plans for the new cathedral were met with some resistance, as many people wanted to rebuild the cathedral in a more traditional Gothic style. However, Wren eventually convinced the commission to approve his plans for a more modern, baroque-style cathedral, which he felt would better reflect the changing times.

The rebuilding of St. Paul's Cathedral took several decades to complete, with construction beginning in 1675 and finishing in 1710. Wren oversaw every aspect of the project, from the design of the building to the hiring of the workers.

Wren's design for the new cathedral was based on a Latin cross, with a central dome that would be supported by four smaller domes. The dome, which was inspired by the dome of St. Peter's Basilica in Rome, would become one of the most iconic features of the new cathedral.

To create the blueprints for the new cathedral, Wren used a combination of hand-drawn sketches and mathematical calculations. He also used scale models to help visualize the final design and make adjustments to the plans as needed.

The structure of the new St. Paul's Cathedral was built using a combination of stone, brick, and timber. The exterior was adorned with intricate carvings and sculptures, while the interior featured ornate decorations and artwork.

One of the most impressive features of the new cathedral was its dome, which was the largest in the world at the time. The dome was made up of three layers, with an outer shell made of lead that weighed over 800 tons.

Overall, the rebuilding of St. Paul's Cathedral was a massive undertaking that required the work of thousands of workers over several decades. However, the end result was a magnificent masterpiece of baroque architecture that still stands as one of the most iconic landmarks in London today.